The invention relates to a spindle assembly for a tire inflation system.
Tire inflation systems for industrial or agricultural vehicles such as trucks or tractors are designed to measure and control the fluid pressure of one or several pneumatic tires of the vehicle. Typically, such a tire inflation system comprises a tire fluid pressure control unit including a fluid source and fluid pressure measuring means and fluid lines through which the control unit and the pneumatic tire are in fluid communication with each other. The control unit is configured to inflate and deflate the tire through the fluid lines.
Since it is desirable that the tire can be inflated and deflated during operation of the vehicle, tire inflation systems known from the prior art comprise rotary seal arrangements which are disposed between a vehicle spindle and a wheel hub on which the wheel and the tire are mounted. Said rotary seal arrangements generally include sealing means disposed on the spindle and/or on the wheel hub wherein a first portion of the sealing means is in sliding sealing contact with a second portion of the sealing means, the sealing means thereby forming a dynamical annular seal chamber through which fluid can be transported from the control unit to the rotating tire and vice versa.
Due to high fluid pressure in the fluid lines and in particular in the annular seal chamber, fluid may at times be leaked out of the annular seal chamber. Since contamination of lubricants with the fluid leaked out of the annular seal chamber is to be avoided, means for efficiently leading away the leaked out fluid are required.
US 2008/0314487 A1 relates to the discharging of leakage air from leakage reception spaces which are arranged on axially opposing sides of an annular space. According to an embodiment illustrated in FIG. 5 of US 2008/0314487 A1, the discharging of leakage air from the reception spaces can be realized by means of bores which are arranged in a sheet metal ring of a seal housing. However, in this arrangement leakage air can be discharged only in the absence of filling air pressure, thereby limiting the use of the described seal arrangement.